Naomi Malek of Denver becomes visibly upset Tuesday while listening to testimony about the Aurora theater shootings during a House Judiciary Committee hearing on a bill requiring background checks for private gun sales and transfers. The committee passed the bill 7-4.

Katharine Zink, center, of Colorado Springs listens to testimony given before the House Judiciary Committee on House Bill 1229 at the state Capitol in Denver on Tuesday. The measure would require background checks for any transfer of a firearm. "There should be background checks in private sales," Zink said.

Over the objections of hundreds of gun-rights supporters who showed up to pack a Capitol hearing room, a Colorado House Committee on Tuesday passed a bill requiring background checks for private gun sales and transfers.

The hearing on House Bill 1229 marked the first clash Tuesday in an all-day battle over two gun-control bills, one on so-called universal background checks and the other on limiting high-capacity gun magazines.

The first bill before the House Judiciary Committee, House Bill 1229, would require a background check for any transfer of a firearm except in certain instances such as those involving antique firearms or gifts between immediate family members. Critics of the bill say it is unenforceable without gun registration.

Rep. Rhonda Fields, D-Aurora, a lawmaker representing victims of the Aurora theater shooting and whose own son was killed by gun violence, is the co-sponsor of the background checks bill.

Fields noted that a Denver Post poll done in January showed 83 percent of Coloradans support background checks for all gun sales.

While purchasers must undergo a background check when buying from a gun dealer, private sales between individuals do not have this requirement. Fields said only 40 percent of all gun sales undergo background checks, and she and other supporters pointed to a survey of prison inmates in which they said 80 percent who used handguns in a crime said they acquired them through private sales.

“The private-sale loophole is just a way for criminals to skirt around our current background check,” Fields said.

Testimony also came from David Chipman, a former agent with the U.S. Bureau of Alcohol, Tobacco and Firearms who helped with rescue efforts in the 9/11 and Oklahoma City bombing events.

But there were far more opponents who packed the Capitol hearing room than supporters of the bill.

They included Daniel Carey, a state lobbyist for the National Rifle Association, who said the bill wouldn’t stop any illegal gun sales but would put an unjust burden on law-abiding citizens.

“Criminals don’t abide by the law,” Carey said. “That’s what makes them criminals.”

James Winchester, former vice president of the Colorado State Shooting Association and one of the writers of the original law setting up background checks, also testified against the bill.

He said the Colorado Bureau of Investigation is not honoring the current three-day requirement in law for the checks. Typical waiting time for the checks are more than a week because of a backlog caused by a surge in gun purchases.

The committee passed the bill on a 7-4 party-line vote, and it now must go to the House Appropriations Committee before it can head to the full House.

The Larimer County coroner on Sunday performed an autopsy on the body found on a farm just east of Loveland Saturday, but the office will not release the cause of death or the identity of the person until they can track down next of kin.